Different immune functions of peripheral blood, regional lymph node, and tumor infiltrating lymphocytes in lung cancer patients

Immune functions of peripheral blood (PBL), regional lymph node (RLNL), and tumor infiltrating lymphocytes (TIL) were evaluated in lung cancer patients. PBL had many natural killer (NK) cells and the highest NK activity, and it showed the highest augmentation of NK activity by interferon-gamma (IFN-gamma) + recombinant interleukin-2 (rIL-2) among the three groups of lymphocytes. PBL had high lymphokine-activated killer (LAK) activity of against a broad spectrum of cell lines and moderate activity against autologous tumor cells by increased effector to target (ET) ratio but the lowest ability of IL-2 production of the three groups of lymphocytes. The RLNL not associated with tumor metastasis had a few NK cells and lower NK activity than PBL, but its LAK activity was almost the same but not greater than that of PBL. RLNL had the highest ability of IL-2 production among the three groups of lymphocytes. All activities of RLNL associated with tumor metastasis were lower than those not associated with tumor metastasis. TIL exclusively consisted of T-cells, especially cytotoxic/suppressor T-lymphocytes. NK activity and lymphocyte blastogenesis of TIL were lower than those of other groups. The LAK activity of TIL differed greatly with the case, and it was the highest against autologous tumor cells among the three groups of lymphocytes in three of eight cases. These findings showed that PBL, RLNL, and TIL had characteristic subpopulations of lymphocytes and different functions of host immune responses in lung cancer. Efficient augmentation of the characteristic immune responses will lead to a more effective total cancer therapy.     

Oral administration of OK-432 (picibanil). (8th report) clinical application: its immunomodulatory effects on the patients with gastrointestinal cancers

A streptococcal preparation, OK-432 at a dose of 5 KE was orally administered to the patients with gastric or colorectal cancer for 7 approximately 14 days before operation, and its immunomodulatory effects on peripheral blood lymphocytes (PBL), regional lymph node lymphocytes (RLNL) and tumor infiltrating lymphocytes (TIL) were assessed. OK-432 treated group included 5 gastric and 6 colorectal cancers, and control group included 6 gastric and 8 colorectal cancers. After oral administration of OK-432 the proportion of Leu 7+ and Leu 11+ cells in PBL increased, and NK cell activity of PBL also was augmented. The proportion of OKT8+ cells increased in PBL and those of OKT3+ cells and OKT8+ cells decreased in RLNL after oral administration of OK-432. The responsiveness of TIL to autologous tumor extracts in the presence of interleukin-2 was enhanced in oral OK-432 group. These results indicate that oral OK-432 affects on NK and T cells and augments the antitumor immunity of the patients with gastrointestinal cancer.     

Lymphokine-activated killer-cell function of lymphocytes from peripheral blood, regional lymph nodes and tumor tissues of patients with oral cancer

Lymphokine-activated killer (LAK) cells, generated from peripheral blood lymphocytes (PBL) from patients with oral cancer or oral leukoplakia and from healthy donors showed comparable lysis of 6 target tumor cell lines, including 3 derived from head and neck and oral cancers. The tumor burden of the host did not appear to influence the systemic LAK activity. LAK activity of lymphocytes infiltrating the tumor tissues (TIL) was also comparable to that of the PBL. Both TIL and PBL showed a parallel increase in proportion of HNK-I+ and CD-25+ cells upon activation with IL-2. The lymph-node lymphocytes (LNL) from metastatic (met) and non-metastatic (non-met) draining lymph nodes, however, showed reduced LAK activity and an increase in CD8+ cells, in addition to CD25+ and HNK-I+ cells, when cultured with IL-2. When IL-2-activated LNL were co-cultured with autologous PBL during IL-2 activation of the latter, a strong suppressive effect was exerted by LNL. In contrast, IL-2-activated PBL did not suppress autologous LAK generation in spite of an increase in CD8+ cells seen after activation with IL-2. Frequency distribution of LAK precursors was significantly lower in LNL than in PBL from oral cancer patients. LAK precursor frequency in TIL was comparable to that of PBL. The results show that, in oral cancer, regional lymph nodes may not have adequate IL-2-inducible cytotoxic potential, due to a reduced number of LAK progenitors and possible activation of suppressor cells. Alternatively, TIL can be a potential source for LAK cell function.     

LAK1 antigen defines two distinct subsets among human tumour infiltrating lymphocytes.

Both lymphokine activated killer (LAK) cells and specific cytotoxic T lymphocytes appear to play a role in tumour immunity. Tumour infiltrating lymphocytes (TIL) which display a CD56+ phenotype (both CD3+ and CD3-) are also likely to possess anti-tumour activity. We have previously described a 120 kDa surface antigen, termed LAK1, expressed on a subset of human peripheral blood lymphocytes (20-50%) with both NK and LAK activity. The aim of the present study was to determine whether LAK1 antigen is able to distinguish among TIL two populations of effector cells displaying either specific or non MHC-restricted (NK/LAK) activity. We showed that about 25% of freshly derived TIL were weakly stained with anti-LAK1 monoclonal antibody and most of them were also CD3+ CD56-. After culture in recombinant interleukin-2 the majority of TIL were CD3+ CD56- and the percentage of LAK1+ cells increased up to 50%. Among cloned TIL, only those lacking LAK1 antigen displayed a specific cytotoxicity against the autologous tumour, whereas the non-lytic clones were able to produce both tumour necrosis factor and gamma-interferon. Moreover, when TIL from a renal cell carcinoma were fractionated into LAK1- and LAK1+ populations, the specific lytic activity was mainly evident when LAK1- lymphocytes were used as effector cells. Conversely, LAK activity was confined to the LAK1+ subset.     

Cytotoxic potential despite impaired activation pathways in T lymphocytes infiltrating nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) is an epithelial tumor consistently associated with EBV. The histological picture is characterized by a strikingly abundant lymphocytic infiltrate. Furthermore, the epithelial tumor cells present several immunological characteristics which suggest an important role for tumor-infiltrating lymphocytes (TIL) in the biology of this tumor. The present study reports the phenotypic and functional characterization of TIL from NPC obtained after enzymatic digestion of 15 NPC biopsies. Flow cytometric analysis of TIL suspensions indicated that most TIL were mature CD3+ T lymphocytes (mean = 60%) with a variable CD4/CD8 ratio. Most TIL were TCR alpha/beta-positive (mean = 55%) and only a few TCR gamma-delta-positive cells could be identified. A small percentage (mean = 9%) displayed an activated phenotype (CD25+, HLA class II+). Using limiting dilution analysis, we found that the average frequency of proliferative T-lymphocyte precursors (PTL-P) is lower among TIL (1/40) than in autologous (1/7) or normal PBL (1/1.4). Moreover, sorting experiments have shown that this defect is significantly more pronounced in the CD8+ than in the CD4+ TIL subset. Accordingly, the TCR and the CD2-mediated antigen-independent pathways of activation were impaired. Different types of cytotoxic precursor could be detected. These included lectin-dependent cell cytotoxicity (LDCC) and NK-like or lymphokine-activated killer (LAK) activity. Interestingly, some TIL from NPC were able to lyse an NPC tumor (C15) maintained in nude mice. Thus, despite impaired activation pathways, the cytolytic potential of proliferating TIL in NPC is preserved.     

Enhancing effect of pokeweed mitogen on the proliferation and the cytotoxicity of lymphokine-activated killer cells.

In order to obtain more potent lymphokine-activated killer (LAK) cells for use in adoptive immunotherapy, pokeweed mitogen (PWM) was added to the culture medium for the initial 24-48 h of culturing. The proliferation rate of PWM-stimulated LAK cells reached about 1000-fold after 3-week culture. This rate was nearly the same as that of LAK cells stimulated by 10 ng/ml of OKT3, the mouse anti-CD3 monoclonal antibody. However, the cytotoxicity of PWM-stimulated LAK cells was significantly more potent than that of OKT3-stimulated LAK cells. Phenotypic analysis revealed that PWM-stimulated LAK cells were CD3+CD56(+)-dominant while OKT3-stimulated LAK cells were CD3+CD56(-)-dominant. About half of CD3+CD56+ PWM-stimulated LAK cells was CD8+. These results suggest that more efficient adoptive immunotherapy is possible by using high-dose PWM-stimulated LAK cells with more potent cytotoxicity. Interleukin-1 beta and tumor necrosis factor alpha were significantly increased in the culture media after 24-h incubation with 1 micrograms/ml of PWM. Secretion of interferon-gamma was not enhanced by this concentration of PWM within 24 h. Therefore, PWM is considered to activate monocytes or macrophages to produce these cytokines in advance, influencing the proliferation and the cytotoxicity of LAK cells.     

Restoration of Tumor-Specific HLA Class I Restricted Cytotoxicity in Tumor Infiltrating Lymphocytes of Advanced Breast Cancer Patients by in vitro Stimulation with Tumor Antigen-Pulsed Autologous Dendritic Cells

Breast tumor infiltrating lymphocytes (TIL) are enriched in tumor-specific cytotoxic T lymphocytes (CTL), and may represent a superior source of CTL compare to peripheral blood lymphocytes (PBL), for adoptive T cell immunotherapy of breast cancer. However, the immunocompetence of TIL and the possibility to consistently restore their tumor-specific lytic activity in vitro remains an open issue. In this study we evaluated the potential of tumor antigen-pulsed fully mature dendritic cell (DC) stimulation in restoring tumor-specific cytotoxicity in anergic TIL populations from advanced breast cancer patients. In addition we have compared tumor-specific T cell responses induced by tumor antigen-loaded DC stimulation of TIL to responses induced from PBL. Although TIL were consistently non-cytotoxic after isolation or culture in the presence of interleukin-2 (IL-2), in matched experiments from three consecutive patients, tumor-lysate-pulsed DC-stimulated CD8+ T cell derived from TIL were found to be significantly more cytotoxic than PBL (p < 0.05). In addition, cytotoxicity against autologous tumor cells was more significantly inhibited by an anti-HLA class I (W6/32) MAb in TIL compared to PBL (p < 0.05). CTL populations derived from TIL and PBL did not lyse autologous EBV-transformed lymphoblastoid cell lines, and showed negligible cytotoxicity against the NK-sensitive cell line K562. Furthermore, in both CD8+ T cell populations the majority of the tumor-specific CTL exhibited a Th1 cytokine bias (IFN-^high/IL-4^low). Taken together, these data show that tumor lysate-pulsed mature DC can consistently restore tumor-specific lytic activity in non-cytotoxic breast cancer TIL. These results may have important implications for the treatment of chemotherapy resistant breast cancer with active or adoptive immunotherapy.     

Enhancing Effect of Pokeweed Mitogen on the Proliferation and the Cytotoxicity of Lymphokine-activated Killer Cells

In order to obtain more potent lymphokine-activated killer (LAK) cells for use in adoptive immunotherapy, pokeweed mitogen (PWM) was added to the culture medium for the initial 24–48 h of culturing. The proliferation rate of PWM-stimulated LAK cells reached about 1000-fold after 3-week culture. This rate was nearly the same as that of LAK cells stimulated by 10 ng/ml of OKT3, the mouse anti-CD3 monoclonal antibody. However, the cytotoxicity of PWM-stimulated LAK cells was significantly more potent than that of OKT3-stimulated LAK cells. Phenotypic analysis revealed that PWM-stimulated LAK cells were CD3⁺CD56⁺-dominant while OKT3-stimulated LAK cells were CD3⁺CD56^--dominant. About half of CD3+CD56+ PWM-stimulated LAK cells was CD8⁺. These results suggest that more efficient adoptive immunotherapy is possible by using high-dose PWM-stimulated LAK cells with more potent cytotoxicity. Interleukin-1β and tumor necrosis factor a were significantly increased in the culture media after 24-h incubation with 1 μg/ml of PWM. Secretion of interferon-γ was not enhanced by this concentration of PWM within 24 h. Therefore, PWM is considered to activate monocytes or macrophages to produce these cytokines in advance, influencing the proliferation and the cytotoxicity of LAK cells.     

Dendritic cells stimulate the expansion of PML-RAR alpha specific cytotoxic T-lymphocytes: its applicability for antileukemia immunotherapy

Dendritic cells (DC), the most potent "professional" antigen-presenting cells, hold promise for improving the immunotherapy of cancer. In this study, we investigated the ability of normal donor DC pulsed ex vivo with 12 mer PML-RAR alpha (A) peptide (SGAGEAAIETQS) to generate peptide specific autologous cytotoxic T-lymphocytes. The peptide pulsed DC-primed peripheral blood lymphocytes (PBL) displayed significantly higher cytotoxic activity compared with that of peptide non-pulsed DC-primed PBL against peptide-pulsed autologous macrophages (P<0.001). Both CD8+ and CD4+ T lymphocytes were involved in the effector cell populations. The PML-RAR alpha peptide-pulsed DC-primed T-cells were significantly superior in their production of GM-CSF and TNF-alpha, compared with peptide non-pulsed DC-primed T-cells. These intriguing preclinical studies, suggest that PML-RAR alpha pulsed-DC could be a promising immunotherapeutic modality for patients with acute promyelocytic leukemia.     

人肿瘤浸润淋巴细胞（TIL）的抗肿瘤活性及与外周血淋巴细胞...

In order to search for more efficient effector cells than the classical LAK cells for tumor immunotherapy, antitumor activity of TIL was studied. Although fresh TIL were unable to kill both NK-sensitive K562 and NK-resistant Anip 973 targets, rIL-2 activated TIL from 8 lung carcinoma and 4 gastric cancer patients did express significant cytotoxicity against allogeneic solid tumor targets Antitumor activity of activated TIL was more efficient than that of activated autologous PBL By limiting dilution assay, TIL were shown to have a higher frequency of LAK precursors than PBL.     

Human tumor-infiltrating lymphocyte (TIL) cytotoxicity facilitated by anti-T-cell receptor antibody

Long-term growth of tumor-infiltrating lymphocytes (TIL) in high concentrations of rIL-2 is required for generation of therapeutic numbers of cells for adoptive immunotherapy of human cancer. Under these conditions rIL-2 promotes both anti-tumor cytotoxicity and lymphocyte growth from tumors of several histological types. In a series of 16 consecutive tumors, studies of TIL-mediated cytotoxicity against different tumor targets were characterized by an initial strong tumor-non-specific cytotoxicity. With time, TIL bulk cultures became non-cytotoxic against all targets (median time = 38 days). Non-cytotoxic TIL bulk populations were capable of mediating strong cytotoxic responses if pre-treated with anti-T-cell antigen receptor antibody (TcR) before addition to targets. TIL populations were not, however, uniformly susceptible to anti-TcR-mediated cytotoxicity. Anti-TcR-mediated cytotoxicity was confined to CD8+ bulk populations (defined as populations with a CD4/CD8 ratio less than 1), with virtually no cytotoxicity observed in CD4+ populations (CD4/CD8 ratio greater than 2, (p less than 0.01). Both CD4 and CD8 populations expressed TcR antigen reactive with anti-TcR antibody. These results indicate that, despite poor in vitro anti-tumor cytotoxicity in short-term assays, CD8+ TIL are fully competent cytotoxic effector cells when subjected to strong activation signals via the TcR complex. In addition, these results imply that adoptively transferred CD4+ populations of TIL have in vivo biologic functions quite distinct from those of CD8+ populations and, further, that disparate clinical outcomes could reasonably be expected from the adoptive transfer of either population alone.     

Antitumor activity of regional lymph node lymphocytes in patients with lung cancer

Cytotoxic activities of regional lymph node lymphocytes (RLNL) and peripheral blood lymphocytes (PBL) of 49 primary lung cancer patients who were subjected to surgical resection were examined by 4 h 51Cr release assay. PBL showed significantly lower cytotoxicity against autologous tumor cells than against K562 and QG-56. On the other hand, RLNL exhibited the same level of cytotoxicity against autologous tumor cells as PBL, although the cytotoxicities against K562 and QG-56 were low. Cytotoxicity of RLNL against autologous tumor cells exhibited a significant degree of depression with the advance of stage, T and N factors. Cytotoxicity of PBL did not significantly change as the stage progressed. When both PBL and RLNL were cultured with purified interleukin-2 (p-IL2) in vitro, their cytotoxic activities were markedly augmented and the cytotoxicities could not be diminished by the treatment with anti-Leu-7 + anti-Leu-11b + C'. These facts indicate that the augmented cytotoxicity may be due to lymphokine activated killer (LAK) cells.     

Effects of Interleukin-12 on the Induction of Cytotoxic T Lymphocytes from the Regional Lymph Node Lymphocytes of Patients with Lung Adenocarcinoma

Lung cancer-specific cytotoxic T lymphocytes (CTL) were induced by repeated stimulations of regional lymph node lymphocytes (RLNL) in lung cancer patients with either autologous or HLA-A-locus-matched tumor cells. To investigate the effect of interleukin-12 (IL-12), IL-12 was added during the stimulation of RLNL from HLA A24 / adenocarcinoma patients with either autologous tumor cells or HLA A24-positive adenocarcinoma cells (PC-9) in combination with, or instead of interleukin-2 (IL-2), and then the cytotoxic activity, cytokine production and populations of the lymphocyte subsets were examined. The addition of IL-12, or the substitution of IL-2 by IL-12 was found to enhance the cytotoxic activity and the cytokine production (IFN-γ, GM-CSF) of the CTL as compared with IL-2 alone. The cytotoxic activity and cytokine production were both partially inhibited by anti-MHC-class I monoclonal antibody. The CTL thus induced by IL-12 had a higher proportion of CD3⁺/CD56⁺ cells than the CTL induced with IL-2 alone. The positively selected CD8⁺/CD56^– lymphocytes showed PC-9-specific cytotoxic activity, because the population did not show any cytotoxicity to K562 or A549 (HLA-A26/A30). However, the CD3⁺/CD56⁺ lymphocytes were cytotoxic to both PC-9 and K562. In conclusion, IL-12 is considered to be a useful cytokine for both the induction of lung-cancer specific CTL and the augmentation of non-MHC-restricted cytotoxicity against tumor cells, and may be applicable for adoptive immunotherapy using CTL.     

The heterogeneity of target recognition by lymphokine-activated killer precursor cells

Lymphokine-activated killer (LAK) cells were generated from peripheral blood lymphocytes (PBL) that were depleted of mature cytotoxic natural killer (NK) cells. PBL NK activity was abolished by pretreatment of effector cells with the toxic lysosomotropic agent L-leucine methyl ester (LME) or by depletion of effector cells by K562 monolayer absorption (MA). Both treatments markedly reduced the proportion of cells expressing NK-associated markers such as CD 16 (Leu 11b, B73.1), Leu 7, and NKH-1 (Leu 19), whereas these treatments had minimal effects on cells expressing T cell markers (CD 3, CD 4, and CD 8). LME and MA also drastically decreased the proportion of K562 target-binding lymphocytes. LAK activity against NK-sensitive and NK-resistant targets can be generated from the NK cell-depleted PBL by incubation with interleukin-2. Peak LAK activity generated from MA-treated PBL was later than the peak of LAK activity generated from either untreated or LME-treated PBL. Although MA of PBL on NK-resistant S4 sarcoma targets had little effect on NK activity, LAK activity against both K562 and S4 targets was reduced. These results suggest that there are at least three LAK precursor subpopulations in PBL: mature NK cells that can bind and kill K562 targets (LME-sensitive and MA-sensitive); "pre-NK" cells that can bind but cannot kill (LME-resistant and MA-sensitive); and non-NK cells that cannot bind and cannot kill K562 targets (MA-resistant).     

The Heterogeneity of Target Recognition by Lymphokine-activated Killer Precursor Cells

Lymphokine-activated killer (LAK) cells were generated from peripheral blood lymphocytes (PBL) that were depleted of mature cytotoxic natural killer (NK) cells. PBL NK activity was abolished by pretreatment of effector cells with the toxic lysosomotropic agent l -leucine methyl ester (LME) or by depletion of effector cells by K562 monolayer absorption (MA). Both treatments markedly reduced the proportion of cells expressing NK-associated markers such as CD 16 (Leu 11b, B73.1), Leu 7, and NKH-1 (Leu 19), whereas these treatments had minimal effects on cells expressing T cell markers (CD 3, CD 4, and CD 8). LME and MA also drastically decreased the proportion of K562 target-binding lymphocytes. LAK activity against NK-sensitive and NK-resistant targets can be generated from the NK cell-depleted PBL by incubation with interleukin-2. Peak LAK activity generated from MA-treated PBL was later than the peak of LAK activity generated from either untreated or LME-treated PBL. Although MA of PBL on NK-resistant S4 sarcoma targets had little effect on NK activity, LAK activity against both K562 and S4 targets was reduced. These results suggest that there are at least three LAK precursor subpopulations in PBL: mature NK cells that can bind and kill K562 targets (LME-sensitive and MA-sensitive); "pre-NK"cells that can bind but cannot kill (LME-resistant and MA-sensitive); and non-NK cells that cannot bind and cannot kill K562 targets (MA-resistant).     

Clinical application of adoptive immunotherapy by cytotoxic T lymphocytes induced from tumor-infiltrating lymphocytes

The tumor-infiltrating lymphocytes (TIL) were cultured with interleukin 2 (IL-2) to induce the cytotoxic T lymphocytes possessing autologous tumor-killing activity from 21 cancer patients (11 with solid tumor and 10 with malignant peritoneal or pleural effusions), and transferred into 7 patients as IL-2-activated TIL adoptively. The clinical application of activated TIL by adoptive transfer could result the complete regression of malignant pleural effusions in a patient with pancreatic cancer, and the nearly complete regression of malignant ascites in a patient with gastric cancer. The autologous tumor cells were isolated at the purity of more than 90% by Ficoll-Hypaque and Percoll discontinuous gradients, and then the TIL were cultured with IL-2 until 4 weeks. The optimal concentration of IL-2 was 1,500 IU/ml to obtain maximum proliferation and autologous tumor killing activity. The cytotoxic activities of activated TIL at 3 weeks-incubation was 72 +/- 15, 42 +/- 26, 27 +/- 21 and 22 +/- 15% against K562, Daudi, KATO-III and autologous tumor, respectively. By negative selection method, it was clarified that the killer cells recognizing autologous tumor consisted of CD4 or CD8 positive T lymphocyte in 43% of patients. The CD8 positive cells and CD56 positive cells increased, the CD4 positive cells and CD16 positive cells decreased by flow cytometry. The activated TIL could lyse not only cultured tumor cell lines, also other autologous tumor cells. The CD56+ cells were isolated by the Panning method, these cells could not lyse autologous tumor cells. Thus, it was indicated that the cytotoxic T lymphocytes recognizing autologous tumor could be generated from TIL and the adoptive immunotherapy of activated TIL was effective in cancer therapy.     

Human melanoma-mediated inhibition of autologous CD4+ helper tumor-infiltrating lymphocyte growth in vitro.

Tumor-infiltrating lymphocytes (TIL) were isolated from a human melanoma metastatic to the abdomen. The TIL were 99% CD3+ and 99% CD4+ and CD8-. They were dependent on interleukin-2 (IL-2) for growth, as measured in a thymidine uptake assay, and were not cytotoxic to autologous or allogeneic melanoma or K562. When co-cultured with irradiated autologous tumor cells, or tumor cell supernatants, the TIL not only did not respond, but the IL-2-dependent growth was inhibited significantly. Inhibition occurred during the first 24 hours of co-culture and persisted as long as the tumor was present. After being washed free of inhibitory tumor cells, the TIL again were able to grow in the presence of IL-2, indicating that the inhibition was not caused by irreversible toxicity mediated by the tumor. Addition of excess IL-2 did not reverse the inhibitory effect, but addition of indomethacin, an inhibitor of cyclooxygenase and prostaglandin synthesis, partially blocked the inhibition. These data show melanoma-mediated inhibition of induction and expansion of human T-cells in vitro, which may reflect one of the mechanisms of inhibition of cellular responses in vivo. These results stress the need to examine the techniques for optimal in vitro expansion of tumor-specific TIL or cytotoxic T-cells for adoptive immunotherapy.     

Allostimulation of patients' lymphocytes generates both T and NK-like cells cytotoxic for autologous melanoma

Killing of autologous melanoma (auto-Me) was obtained with pooled allostimulated peripheral blood lymphocytes (PBL) in 34/42 cases and found not to be due to a cross-reactivity between melanoma and allogeneic normal antigens. To see whether generation of tumour cytotoxic PBL by allostimulation was due to release of IL-2, PBL from 34 patients were divided into two aliquots and stimulated either by alloantigens or IL-2. Allostimulated PBL were cytotoxic for auto-Me in 30/34 cases (85%) whereas IL-2 generated tumour cytotoxic cells in 22/34 cases (64%). Lysis of K562, a target for monitoring NK-like activity, was obtained in 95-100% of cases with both stimuli. A similar frequency of OKT3+, OKT4+, OKT8+ and HNK1+ cells was found in PBL activated by allostimulation and IL-2, whereas a higher frequency of OKM1+ cells was evident in IL-2-stimulated PBL. Cold-target competition studies indicated that allostimulation generated at least two different types of effectors, one lytic to auto-Me but not to K562, and the other which lysed both targets. Allostimulated, FACS-separated T3- cells killed both auto-Me and K562 cells whereas T3+ cells lysed only auto-Me. It is concluded that allostimulation generated two subpopulations of auto-Me killer cells, one of the T lineage and the other NK-like, which both can destroy auto-Me targets.     

Lymphokine-activated killer (LAK) cells. Analysis of factors relevant to the immunotherapy of human cancer

Lymphokine-activated killer (LAK) cells can be generated by incubating fresh peripheral blood lymphocytes (PBL) in Interleukin-2 (IL-2). LAK cells kill fresh autologous and allogeneic human tumor cells in vitro. This study analyzes aspects of LAK cells that make them a promising candidate for the adoptive immunotherapy of human cancer. LAK cells can be generated from PBL of normal individuals and tumor-bearing patients. Pure, recombinant IL-2 generates LAK cells capable of killing a wide variety of tumors including sarcomas and cancers of the colon, pancreas, adrenal gland, and esophagus. Thirty-six of 41 (88%) fresh, noncultured, human tumor cell suspensions prepared from surgical specimens were lysed by LAK cells in a standard 4-hour chromium-release assay. Normal PBL were not killed. LAK cells can be expanded in vitro for periods longer than 2 months, potentially more than 10(20)-fold, while maintaining lytic ability. These results and the demonstrated efficacy of LAK cells in the therapy of murine tumors make LAK cells a candidate for clinical use in the adoptive immunotherapy of human cancer.     

Lymphokine-activated killer activity in long-term cultures with anti-CD3 plus interleukin 2: identification and isolation of effector subsets

Peripheral blood lymphocytes cultured in recombinant interleukin 2 during 3 to 5 days (short-term cultures) develop the ability to lyse natural killer-resistant tumor lines and fresh tumor cells, i.e., express lymphokine-activated killer (LAK) function. Phenotypic analysis has shown these cells to be natural killer cells, i.e., CD16+ and/or Leu 19+ cells. CD3+,CD16- T-cells, instead, develop very low LAK function in these cultures. We recently reported the development of long-term (up to 21 days) cultured cells with LAK activity by stimulation with OKT3 + interleukin 2(IL2). These culture conditions repeatedly resulted in a several hundred-fold expansion in cell number. Specific LAK activity on Day 14 of culture was comparable to that of 3-day LAK cultures and could be further enhanced by the addition of interleukin 1 beta, beta-, or gamma-interferon. Total LAK activity was greatly increased in OKT3 + IL2 cultures over that found in short-term cultures. Isolation of effectors mediating LAK function in long-term cultures stimulated with OKT3 + IL2 showed that both CD3+,CD16- cells and CD16+,CD3- cells tested on Day 14 of culture expressed equivalent levels of LAK activity as shown by lysis of natural killer-resistant targets, HL60 and Daudi. Further dissection of the subpopulations developing LAK activity demonstrated that, in addition to CD16+,CD3- cells, CD3+, CD4-,CD8- cells and Leu 19+,CD3-,CD16- cells also developed high LAK activity in long-term cultures with OKT3 + IL2. Further, long-term culture with OKT3 + IL2 induced increases in the numbers not only of CD3+,CD4-,CD8- cells but also of CD16+,CD3- and Leu 19+,CD3-,CD16- cells. Although there is a significant increase in the number of CD3+,CD8+ cells, neither these, nor the CD3+,CD4+ cells, mediate LAK activity to the same extent as the populations mentioned above.